Do Multimedia Contents increase the effectiveness of learning?

In an engineering online degree, contents are usually given in a few different modalities: text, hypertext, video-clips and simulators or virtual laboratories. The aim of this study is to find out about their appropriateness for learning electrical engineering. In this paper, comparative studies on what kind of contents are better for the effective learning of some technical concepts are presented. The analysis is based on pilot tests in which students are divided into two statistically equivalent groups. Students in each group study with a different modality. Then the results from the two groups are compared. Besides these tests, student's opinion polls are analyzed. The results obtained demonstrate how multimedia contents are more efficient than texts in the learning process of certain concepts. Nevertheless, problems or failures in the technology used have a very negative effect